[UNIX] UnixWare 7 lpsystem Vulnerable to an Exploitable Buffer Overflow

From: support@securiteam.com
Date: 10/08/01 

From: support@securiteam.com
To: list@securiteam.com
Subject: [UNIX] UnixWare 7 lpsystem Vulnerable to an Exploitable Buffer Overflow
Message-Id: <20011008124156.0CE8B138C4@mail.der-keiler.de>
Date: Mon,  8 Oct 2001 14:41:56 +0200 (CEST)

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  UnixWare 7 lpsystem Vulnerable to an Exploitable Buffer Overflow
------------------------------------------------------------------------

SUMMARY

SCO UnixWare 7.1's sgid-lps '/usr/sbin/lpsystem' will allow any local user
to gain root privilege.

DETAILS

Vulnerable systems:
UnixWare version 7.1

The lpsystem command is used to define remote systems with which the local
LP print service can exchange print requests. These remote systems are
described to the local LP print service in terms of several parameters
that control communication: Type, Retry and Timeout. These parameters are
defined in /etc/lp/Systems file.

The lpsystem command on the SCO UnixWare 7 has improper bounds checking in
the username argument that can cause a buffer overflow when a lengthy
username is passed.

Proof of concept:
SCO UnixWare 7.1.0 (Lab) (pts/4)

login: XXX
Password:
UnixWare 7.1.0
Lab
Copyright (c) 1976-1998 The Santa Cruz Operation, Inc. and its suppliers.
All Rights Reserved.

# uname -a
UnixWare Lab 5 7.1.0 i386 x86at SCO UNIX_SVR5
#

# ls -la /usr/sbin/lpsystem
---s--x--x 1 root lp 41840 Apr 4 1998
/usr/sbin/lpsystem
#

# /usr/sbin/lpsystem `perl -e '{print "A"x10000}'`
Segmentation Fault - core dumped
#

Patch:
Updates for this daemon are available at SCO's website:
<http://www.sco.com> http://www.sco.com

ADDITIONAL INFORMATION

The information has been provided by <mailto:al3xhernandez@ureach.com>
Alex Hernandez .

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